Arteriosclerosis and Hypertension with Chapters on Blood Pressure.
Journal: JAMA (1920)

Veiitrieular fibrillation TAJ 45.Auricular pxtrasystoles ];{<) 4().A'ontricular cxtrasystolc i;;9 47.Delayed conduction 141 48.Partial lieart block 141 4 SI.Complete heart block 142 "lO.Alternating periods of sinus rhythm and auriculoventricular rliytluu 144 51.Auriculoventricular or "nodal" rhythm 144 52.Influence of mechanical pressure on the right vagus nerve . . . . 144C>'A.Schematic distribution of right and left vagus 145 54.Blood pressure record from a normal reaction to ether 149 55.Chart showing the method of recording blood pressure during an operation 150 56.Method of using blood pressure instrument during operation . . . 15157.Finger-til) palpation of the radial artery 178 58.Finger-tip palpation of the radial artery 178 59.Aneurysm of the heart wall 1!*<3 60.Large aneurysm of the aorta eroding the sternum It'S ARTERIOSCLEROSIS AND HYPERTENSION CHAPTER I ANATOMY With the increased complexity of our modern life comes increased wear and tear on the human organism.''A man is as old as his arteries" is an old dictum, and, like many proverbs, the application to mankind today is, if any- thing, more pertinent than it was when the saying was first uttered.Notwithstanding the fact that the average age of mankind at death has been materially lengthened the increase in years amounting to fourteen in the past one hundred years of history-clinicians and pathologists are agreed that the arterial degeneration known as arteriosclerosis is present to an alarming extent in persons over forty years of age.Figures in all vital statistics have shown us that all affections of the circulatory and renal s^'stems are definitely on the increase.''Arterial diseases of va- rious kinds, atheroma, aneurysm, etc., caused 15,685 deaths in 1915, or 23.3 per 100,000.This rate, although somewhat lower than the corresponding ones for 1912 and 1913, ishigher than that for 1914, and is very much higher than that for 1900, which was 6.1."The great group of cases of which cardiac incompetence, aneurysm, cerebral apoplexy, chronic nephritis, emphysema, and chronic bronchitis are the most frequent and important appear as terminal events in which arteriosclerosis has probably played an important part.Thus, in the sense in which we speak of tuberculosis or pneumonia as a distinct disease, we can not so designate the diseased condition of the arteries.Arteriosclerosis is not a disease sui generis.It is best ?)0AirrEllIOSCLEROSTS the i^recapillary arterioles the muscle no longer forms a continuous layer, l)ut is re])i"esente(l l)y groups of fiber cells that partially wrap around the vessel, and at last are re- l)laced by isolated elements.After the disappearance of the muscle cells the ])lood vessel has become a true capillary.The adventitia shares in the general reduction, and gradually diminishes in thickness until, in the smallest ar- teries, it consists of only a few fibroelastic strands outside the muscle cells."(Piersol's Anatomy.)The large arteries diifer from those of medium size mainly in the fact that there is no sharp line of demarcation between the intima and the media.There is also much more elastic tissue distributed in firm bundles throughout the media, and there are fewer muscle fibers, giving a more compact appearance to the artery as seen in cross section.The predominance of elastic tissue permits of great distention by the blood forced into the artery at every heartbeat, the cali1)er of the tube being less markedly under the control of the vasomotor nerves than is the case in the small arteries, Avliere the muscle tissue is relatively more developed.The adventitia of the large arteries is strong and firm, and is made up of interlacing fil)roelastic tissue, of which some of the bundles are arranged longi- tudinally. VeinsThe walls of the veins are thinner than those of the ar- teries; they contain much loss elastic and muscular tissue, and are, therefore, more flaccid and less contractile.]\lany veins, particularly those of the extremities, are provided with cup-like valves opening toward the heart.These valves, when closed, j^revent the return of the blood to the periphery and distribute the static pressure of the blood column.The bulgings caused by the valves may be seen in the superficial veins of the arm and leg.There are no valves in the veins of the neck, where there is no necessity for such a protective mechanism, gravit}' sufficing to drain the venous blood from the cranial cavitv.Ar.TEPJO.SCLEnoSlS now cliiefly of historical interest.As the author under- stands him, he considered a rui)ture in the media to be the cause of a local widening and consequently the blood could not be distributed evenly to the organ which was supplied by the diseased artery or arteries.Moreover, there was danger of a rupture at the weak spot unless this were strengthened.It was essential for the even distribution of blood that the lumen be restored to its former size.Na- ture's method of repair was a hypertrophy of the subin- timal connective tissue and the formation of a nodule at that point.The thickening was compensatory, resulting in the establishment of the normal caliber of the vessel.Tlioma showed that by injecting an aorta in the subject of such changes, Avith paraffin at a pressure of 160 mm. of mer- cury, these projections disappeared and the muscle bulged externally.He recognized the fact that the character of the artery changed as the years passed, and to this form he gave the name, primary arteriosclerosis.To the group of cases caused by various poisonous agents, or following high peripheral resistance and consequent high pressure, he gave the name, secondary arteriosclerosis.This is a useful but not essential division, as the changes which age and high tension produce may not be different from those produced in much younger persons by some circulating poison.And most important to bear in mind, octogena- rians may have soft, elastic arteries.As the body ages, certain cjianges usually take place in the arteries leading to thickening and inelasticity of their walls.This is a normal change, and in estimating the palpable thickening of an artery, such as the radial, the age of the individual nuist always be considered.Thayer and Fabyan, in an examination of the radial artery from birth to old age, found that, in general, the artery strengthens itself, as more strain is thrown upon it, by new elastica in the intima and connective tissue in the media and adventitia.Up to the third decade there is only INDEX Blood ])rossuro instruments-Cont 'd.Stanton's, 72 technique of, 80 "Tyeos," 77 V. Basch's, 70 V.Recklinghausen 's, 76 mechanism of, 55 normal variations of, 88 ])henomenon, auscultatory, 90 ])recautions when estimating, 181 value of, 181